Liquid metal conduction pump

ABSTRACT

A conduction pump having a simple structure for liquid metal, comprising a coil constituted by a refractory casing containing liquid metal and a metal flow duct connnected to the casing by two end pieces each comprising at least one opening.

United States Patent 1 1 Ertaud et al.

[ LIQUID METAL CONDUCTION PUMP [75] Inventors: Andr Ertaud, Paris;Jacques Panossian, Chaville; Henri Carbonnel, Antony, all of France [73]Assignee: Groupement Atomique Alsacienne Atlantique, LePlessis-Robinson, France [22] Filed: Dec. 22, 1972 [21] Appl. No.:317,842

Dec. 22, 1971 France ..7l/462l1 152'] vs. Ci..' I;..;IIIITLII.'II.II.I.....417Zsb [51] Int. Cl. H02n 4/20 [58] Field of Search 417/50 [56]References Cited UNITED STATES PATENTS 2,756,678 7/1956 Collins 417/50 151 Sept. 24, 1974 3,115,837 12/1963 Campana ..4l7/50 3,442,217 5/1969Hanlin ..417/50 Primary Examiner-William L. Freeh Attorney, Agent, orFirm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A conductionpump having a simple structure for liquid metal, comprising a coilconstituted by a refractory casing containing liquid metal and a metalflow duct connnected to the casing by two end pieces each comprising atleast one opening.

10 Claims, 5 Drawing Figures LIQUID METAL CONDUCTION PUMP The presentinvention concerns a conduction pump having a simple structure forliquid metal, which may be immersed in the said metal.

It is known that conduction pump designates a pump in which the liquidmetal is set in motion by the electromagnetic force produced by thecombined action of a magnetic induction and an electric current flowingperpendicular to the magnetic field, across a section of liquid metalflux.

A pump of that type is the object of French Pat. No. 71,09,159 filed inthe name of the Applicant on Mar. 16, 1971.

According to an embodiment described in the above mentioned patent, thepump comprises:

A first magnetic circuit provided at its upper part with a first feedwinding, and at its lower part with an air gap in which a horizontalmagnetic field is set up;

A rectilinear duct having a vertical axis crossing the said air gap,used for the liquid metal flow;

A coil, whose middle plane is horizontal, constituted by a refractorycasing containing liquid metal in electrical contact at the level of thesaid air gap with the liquid metal flowing in the said duct;

A second magnetic circuit provided, at its upper part, with a supplywinding inducing an electric current in the coil, the direction of thatcurrent being horizontal and orthogonal to the magnetic field in thesection of liquid metal situated in the said air gap.

In that pump, the coil is arranged appreciably below the said first andsecond windings, this enabling the said windings to be above the liquidmetal bath when the coil is immersed in that bath.

The refractory casing of the coil is connected to the duct by means oftwo rigid electrodes ensuring electrical continuity between the liquidmetal contained in the refractory casing and the metal flux flowing inthe duct.

Pumps of the type described in the aforementioned patent give absolutesatisfaction, but the Applicant has attempted to make pumps having asimplified structure and nevertheless having acceptable efficiency,which may be used, for example, in applications where they are calledupon to operate on a discontinuous basis.

To obtain the pump according to the invention which is the object of thepresent application, the Applicant conceived the idea of replacing therigid-electrodes, which were delicate and expensive to manufacture inthe liquid coil pump in the aforementioned patent, by end piecesprovided with at least one opening establishing a communication betweenthe inside of the refractory casing of the coil and the inside of theduct.

Pumps whose coils end in end pieces provided with openings haveacceptable effeciency and have given satisfaction. In particular, thefilling of the coil with liquid metal on starting up the pump, as wellas the discharging of that metal after the stopping of the pump areconsiderably simplified. Indeed, on starting up the pump, the coil isimmersed in a liquid metal bath and filled with that same metal.Moreover, the Applicant has observed that it was possible to improvethat output in a simple way by cancelling an interference flow of metalwhich originated in an opposite direction to that of the metal flow inthe duct.

According to a first variant of the invention, the end pieces areprovided with n openings extended by separations dividing the coil andend pieces into 11 parallel channels.

According to a second variant of the invention, the end pieces areprovided with n openings extended by separations dividing only the endpieces into n parallel channels. I

The following description with reference to the accompanying drawingswill make it easier to understand how the invention may be implemented.

FIG. 1 is a general view of a pump according to the invention.

FIG. 2 shows diagrammatically a conductive coil provided with end piecesaccording to the invention.

FIG. 3 is a first variant of a coil provided with end pieces.

FIG. 4 is a second variant of a coil provided with end pieces.

FIG. 5 shows diagrammatically a particular end piece.

The electromagnetic conduction pump such as that shown in FIG. 1comprises a vertical duct 1 for the liquid metal flow, preferably madeof refractory material crossing the air gap 2 of a first magneticcircuit in the shape of a frame 3.

That frame is connected with a winding 4 situated at the upper part ofthe frame 3 and wound round one of the sides of that frame. The winding4 is fed with alternating current, so as to set up, in the section ofliquid metal situated in the air gap 2, a horizontal magnetic field.That air gap is situated at the lower part of the frame 3.

The pump comprises, moreover, a second magnetic circuit in the shape ofa frame 5, a feed winding 6 situated in the upper part of the frame 5and wound round one of the sides of that frame, and a conductive coil 7having a rectangular cross-section surrounding one of the vertical sidesof the frame 5.

The winding 6 is fed with alternating current so as to induce analternating current in the conductive coil 7. That coil 7 whose middleplane is horizontal is constitued by a refractory casing 8 containingliquid metal. That casing 8 is connected to the duct 1 by two end pieces9, 9 each comprising an opening making the inside of the casing 8communicate with the inside of the duct 1, so that metal may flowbetween the casing 8 and the duct 1. The section of metal situatedbetween the end pieces 9, 9' has the alternating current generated inthe coil 7 passing through it.

The coil 7 is arranged so that the direct current flowing between theend pieces 9 and 9 be orthogonal to the magnetic field set up in the airgap 2 and to the axis of the duct 1. The end pieces 9 and 9' aresituated on either side of the part of the duct 1 arranged in the airgap 2, and the casing 8 comprises a plane part situated facing that partof the duct arranged in the air gap 2, also arranged in the air gap 2.The spire 7 is arranged at an appreciably lower level than the windings4 and 6, so that these windings 4 and 6 be situated appreciably abovethe liquid metal bath when the coil 7, as well as the part of the duct 1situated below that coil are immersed in the metal bath. It is thuspossible, to protect the said windings 4 and 6 against any accidentalrise in temperature which would make good operation of the pumpimpossible.

For the vertical electromagnetic force which is then set up in thesection of metal situated between the end pieces 9 and 9' to remainalways ascending, it is necessary to ensure that the current and themagnetic field be approximately in phase.

FIG. 2 shows diagrammatically a conductive coil 17, constituted by acasing 18 containing liquid metal. That coil has a rectangularcross-section and is connected to the duct 1 by two end pieces 19 and19' each provided with a rectangular opening and 10'.

When the pump is in operation, the metal flux in the duct 1 has anascending direction (vertical arrow F1). Nevertheless, as the Applicanthas observed, an interference flow takes place from top to bottom of theliquid in the end pieces 19 and 19' (arrows F2 and F2). To cancel thatinterference flow, which decreases efficiency, end pieces having severalopenings are manufactured.

FIG. 3 is a first variant of a coil 27 constituted by a casing 28containing liquid metal and ended by two end pieces 29 and 29'connecting that coil 27 to the flow channel 1.

The end piece 29 comprises n openings of equal cross-section, arrangedone below another, such as a, 20b Likewise, the end piece 29' comprisesn openings having an equal surface, such as 20a, 20b The openings 20a,20b 20'a, 20b of the end pieces are extended by horizontal partitionssuch as 2l'a, 2lt situated inside the end pieces and the coil 27. Thesepartitions separate that coil and these end pieces into n parallelchannels 22a, 22b and they are constituted by insulating or conductiverefractory materials, they prevent any interference flow of the liquidmetal from top to bottom in the end pieces 29 and 29 and in the coil 27.

FIG. 4 is a second variant of the conductive coil 37 whose casing 38 isconnected to the duct 1 by two end pieces 39 and 39'. Each end piece 39,39' comprises n equal openings, situated one below another, such as 30a,30b and 30a, 30'b These openings are extended over the length of the endpieces only by horizontal partitions 31a, 31b and 3la, 31b dividing theend pieces into n parallel channels 32a, 32b and 32'a, 32'b Thesepartitions are made of refractory materials and prevent any parasiteflow of liquid metal from top to bottom in the end pieces 30 and 39.

FIG. 5 is an end piece 49 comprising n openings a, 40b whosecross-sections decrease from the lower part of the end piece to theupper part, following the metal flow in the duct, to take into accountthe possible variant of the field along the duct.

The openings 40 are extended by horizontal partitions. End pieces ofthat type give excellent results and enable the electrical resistance ofthe coil on the end of which they are installed to be reduced as much aspossible.

The applicant has manufactured end pieces whose openings were extendedby inclined partitions, this having, in certain cases, improved themetal flow in the duct.

The end pieces are, to great advantage, made of a ceramic substance,cement or compound materials.

Although the end pieces and the coil are manufactured separately, it ispossible, in certain cases, to make this manufacturing easier, tomanufacture simultaneously the end pieces, the casing of the coil andalso the partitions, for example, by moulding in a same mould, so thatthe coil and end pieces then form only a single part.

Although the pump which has just been described appears to afford thegreatest advantages for implementing the invention, it will beunderstood that various modifications may be made thereto without goingbe yond the scope of the invention, it being possible to replace certainof its elements by other elements capable of fulfilling the sametechnical function or an equivalent technical function therein.

We claim:

1. In a liquid metal conduction pump which may be immersed in said metaland which includes:

a first magnetic circuit provided at its upper part with a first feedwinding and at its lower part with an air gap within which a horizontalmagnetic field is set up by energization of a first feed winding, arectilinear duct extending vertically within said air gap for confiningthe liquid metal flow along a vertical axis crossing said air gap, asecond magnetic circuit provided at its upper part with a second supplywinding and a coil carried by said second magnetic circuit having anelectrical current induced therein and having a middle plane portionextending through said air gap of said first magnetic circuit with thedirection of the current being horizontal and orthogonal to the magneticfield in the section of liquid metal situated in said air gap. theimprovement wherein:

opposite sides of said duct at said air gap carry aligned openings andsaid coil comprises a closed refractory casing intersecting saidrectilinear duct and terminating at its ends in open end piecessealingly overlying said openings within respective sides of saidrectilinear duct with said refractory casing containing said liquidmetal,

whereby, a continuous loop of liquid metal flowing in said duct at thelevel of said air gap acts as a low impedance closed loop conductor forcausing a large current to flow across the flow path of the liquid metalpassing axially within the rectilinear duct and at right angles to themagnetic flux path across the air gap.

2. The conduction pump for liquid metal according to claim 1, wherein:each end piece of said casing is constituted by an extension of saidcasing.

3. The conduction pump for liquid metal, according to claim I, wherein:each end piece comprises n openings separated by partitions dividingthat end piece into n parallel channels.

4. The conduction pump for liquid metal according to claim 3, wherein:each end piece of said casing is constituted by an extension of saidcasing.

5. The conduction pump for liquid metal, according to claim 3, wherein:the cross-section of the openings decreases from the lower part of eachend piece to the upper part, following the flow direction of the metal.

6. The conduction pump for liquid metal, according to claim 5, wherein:each end piece of said casing is constituted by an extension of saidcasing.

7. The conduction pump for liquid metal, according to claim 1, wherein:each end piece comprises n openings separated by partitions dividing thecoil and the end pieces into n parallel channels.

8. The conduction pump for liquid metal, according to claim 7, wherein:each end piece of said casing is constituted by an extension of saidcasing.

9. The conduction pump for liquid metal, according upper part, followingthe flow direction of the metal.

10. The conduction pump for liquid metal, according to claim 9, wherein:each end piece of said casing is to claim 7, wherein: the cross-sectionof the openings 5 constituted by an extension of Said Casingdecreasesfrom the lower part of each end piece to the

1. In a liquid metal conduction pump which may be immersed in said metaland which includes: a first magnetic circuit provided at its upper partwith a first feed winding and at its lower part with an air gap withinwhich a horizontal magnetic field is set up by energization of a firstfeed winding, a rectilinear duct extending vertically within said airgap for confining the liquid metal flow along a vertical axis crossingsaid air gap, a second magnetic circuit provided at its upper part witha second supply winding and a coil carried by said second magneticcircuit haviNg an electrical current induced therein and having a middleplane portion extending through said air gap of said first magneticcircuit with the direction of the current being horizontal andorthogonal to the magnetic field in the section of liquid metal situatedin said air gap. the improvement wherein: opposite sides of said duct atsaid air gap carry aligned openings and said coil comprises a closedrefractory casing intersecting said rectilinear duct and terminating atits ends in open end pieces sealingly overlying said openings withinrespective sides of said rectilinear duct with said refractory casingcontaining said liquid metal, whereby, a continuous loop of liquid metalflowing in said duct at the level of said air gap acts as a lowimpedance closed loop conductor for causing a large current to flowacross the flow path of the liquid metal passing axially within therectilinear duct and at right angles to the magnetic flux path acrossthe air gap.
 2. The conduction pump for liquid metal according to claim1, wherein: each end piece of said casing is constituted by an extensionof said casing.
 3. The conduction pump for liquid metal, according toclaim 1, wherein: each end piece comprises n openings separated bypartitions dividing that end piece into n parallel channels.
 4. Theconduction pump for liquid metal according to claim 3, wherein: each endpiece of said casing is constituted by an extension of said casing. 5.The conduction pump for liquid metal, according to claim 3, wherein: thecross-section of the openings decreases from the lower part of each endpiece to the upper part, following the flow direction of the metal. 6.The conduction pump for liquid metal, according to claim 5, wherein:each end piece of said casing is constituted by an extension of saidcasing.
 7. The conduction pump for liquid metal, according to claim 1,wherein: each end piece comprises n openings separated by partitionsdividing the coil and the end pieces into n parallel channels.
 8. Theconduction pump for liquid metal, according to claim 7, wherein: eachend piece of said casing is constituted by an extension of said casing.9. The conduction pump for liquid metal, according to claim 7, wherein:the cross-section of the openings decreases from the lower part of eachend piece to the upper part, following the flow direction of the metal.10. The conduction pump for liquid metal, according to claim 9, wherein:each end piece of said casing is constituted by an extension of saidcasing.